The present invention relates to a control apparatus of a vehicle which includes an engine and an automatic transmission.
Conventionally, JP3196490B2 discloses a device in which, when a vehicle is traveling and performing a gentle slowdown, an engine is stopped automatically and an automatic transmission is changed into a neutral position (i.e., a coast idle stop control is performed), for example. According to the device, fuel consumption is improved by the automatic engine stop, and a less excessive slowdown sensation is given to a vehicle operator who wants the vehicle to perform a coast traveling (inertia traveling) than a case where the engine is stopped automatically and the automatic transmission is changed into a non-neutral position.
When the vehicle performs the coast traveling, it is desirable to perform a coast idle stop control as disclosed in JP3196490B2 in terms of achieving both the improvement of fuel consumption and the less excessive slowdown sensation.
If the operator again steps on an accelerator pedal to give a re-acceleration request while the coast idle stop control is performed, the engine is started and the automatic transmission is changed into the non-neutral position (i.e., given engageable elements are engaged) in order to respond to the re-acceleration request. Moreover, if the operator steps on the brake pedal while the coast idle stop control is performed, this means that the operator requests a greater slowdown than that of the coast traveling (i.e., requesting an engine brake). Therefore, the engine is started and the automatic transmission is changed into the non-neutral position in order to respond to the engine-brake request.
Thus, when the operator requests the re-acceleration or engine brake while the coast idle stop control is performed, the engine is started and the automatic transmission is changed into the non-neutral position in order to respond to such a request. However, since the engine starting especially takes time, it may cause a bad response to the operator's re-acceleration or engine-brake request.
In such a case, in order to perform the coast traveling, a coast idle control may be performed in which the engine is made running idle and the automatic transmission is changed into the neutral position.
Although the coast idle control improves the response to the operator's re-acceleration or engine-brake request while the control is performed, an improvement of fuel consumption may be insufficient because the engine runs idle.